dismiss keyboard when menu is activated

Forces the contentViewController to resign any first registered first responders upon activation of the menu, which in affect forces the keyboard to close if open.


    endEditing:
    Causes the view (or one of its embedded text fields) to resign the first responder status.

    - (BOOL)endEditing:(BOOL)force

    Parameters
    Specify YES to force the first responder to resign, regardless of whether it wants to do so.

    Return Value
    YES if the view resigned the first responder status or NO if it did not.

    Discussion
    This method looks at the current view and its subview hierarchy for the
    text field that is currently the first responder. If it finds one, it asks
    that text field to resign as first responder. If the force parameter is set
    to YES, the text field is never even asked; it is forced to resign.

http://developer.apple.com/library/ios/#documentation/uikit/reference/uiview_class/uiview/uiview.html